The process of removing material from land sites such as mines has been aided in recent years by the development of commercially available computer software for creating digital models of the geography or topography of a site. These computerized site models can be created from site data gathered by conventional surveying, aerial photography, or, more recently, kinematic GPS surveying techniques. Using the data gathered in the survey, for example point-by-point three-dimensional position coordinates, a digital database of site information is created which can be displayed in two or three dimensions using known computer graphics or design software.
For material removal operations such as mining it is desirable to add additional information to this database. Core samples are frequently taken over a site in order to categorize and map the different types and locations of material such as ore, as well as the different concentrations or grades within a given ore type.
Using the above information, a mine plan can be developed. The mine plan can include an evaluation of the amount of topsoil to remove and stockpile or spread for reclamation, and identification of the amount of overburden required to be moved in order to mine the ore. Finally, the plan may include the method with which the actual ore will be mined and removed.
The economy of the mining operation is largely determined by the amount of product processed from the ore removed. To meet output requirements, identification of economical ore concentrations to be processed is important. It is therefore desirable to establish well defined boundaries for the various types and grades of ore to be mined from the site which can be efficiently processed with current methods.
Generally a resource map of the site and the material to be mined is generated with boundaries corresponding to the different types and grades of ore. Surveying and stake setting crews mark the site itself with corresponding flags or stakes.
The mining of the ore is accomplished with mobile or semi-mobile loading machinery equipped with a tool such as a bucket. The loader removes the ore as indicated by the stakes and loads it one bucket at a time into a truck, for example. When the truck is filled, the truckload of ore is transported from the site for processing or stockpiling.
During the loading operation the flags or stakes marking out the various types and grades of ore are vulnerable and are easily disturbed. It may also be difficult for the operator to see the flags, depending on the available light or weather. Additionally, there may be several marked sections that look similar to the mapped area which the operator is trying to locate from the paper copy of the site model.
Since mines are typically set up to handle a given amount of material of given ore concentrations, errors in loading the wrong material from the site can be costly. If a mine inadvertently provides a mill or processing plant with material that is out of specification regarding the concentration of ore, the mine may be liable for compensating the plant for any related production consequences.
Therefore, two fundamental issues involved with mining a land site are knowing the work cycle of the mobile machine, e.g. when it is loading and dumping material, and what type of material is being mined. There are currently some solutions to this. However these solutions consist of using expensive sensors such as payload monitoring systems to determine when the bucket is being loaded, and using one or more GPS sensors located on the bucket to determine the position of the bucket on the work site. Since reducing the cost of mine operation is a primary concern, a low cost solution to monitoring the work cycle of a mobile machine, and the type of material being loaded is desired.
The present invention is directed to overcoming one or more of the problems as set forth above by monitoring the work cycle of a mobile machine on a land site.